Field of the Invention
The present invention relates to a thermoelectric device having a flat tube and a first thermoelectric module and a second thermoelectric module, whereby the thermoelectric modules each have a housing with at least two opposite first walls, whereby a plurality of thermoelectric elements are arranged between the first walls of the housing, whereby the thermoelectric elements have opposite surfaces, which in each case are in thermal contact with one of the first walls of the housing of the thermoelectric module. In addition, the invention relates to an arrangement of a thermoelectric device in a heat exchanger.
Description of the Background Art
In motor vehicles a major part of the energy stored in fuel is converted to heat. Apart from being used for heating the interior, for example, the heat is also released partially unused via the exhaust gas.
This has a negative influence on the overall efficiency of the vehicle. In order to increase the efficiency and thereby to reduce CO2 emissions during operation, it is worthwhile to make the energy bound in the exhaust gas utilizable.
The use of thermoelectric devices is necessary to achieve this. These thermoelectric devices have thermoelectrically active materials, which allow the generation of electrical energy. For this purpose, the thermoelectric materials should be exposed to a temperature difference.
The exhaust gas line lends itself as a hot source particularly in the motor vehicle. The exhaust gas temperatures are sufficiently high over the entire exhaust gas line, so that a thermoelectric device can be integrated at many locations in the exhaust gas line.
A coolant stream of the vehicle, for example, lends itself as a cold source. For this purpose, either an already present coolant circuit can be expanded, or if necessary an additional circuit can be integrated.
The publications EP 1230475 B1 (which corresponds to U.S. Pat. No. 6,474,060), EP 1475532 A2 (which corresponds to U.S. Pat. No. 7,100,369), WO 2007026432, JP 10281015AA, JP 2000282960AA, JP 2004068608AA, JP 2005083251AA, or JP 2005117836AA in fact disclose approaches by using such a thermoelectric device; however, these implementations are not very efficient because of the disadvantageous connection of the thermoelectric modules to a heat exchanger.
To assure an especially efficient use of a thermoelectric device, it is very important that the thermoelectric elements within the thermoelectric modules are connected especially advantageously to the fluids. In particular, a low heat transfer coefficient is advantageous to be able to produce the maximum benefit from the temperature difference of the two fluids, or in an alternative design to realize the most effective heat pump possible with as low a current consumption as possible.
At present, particularly disadvantageous in the prior art is the connection of the thermoelectric elements to the fluid, particularly with respect to a lowest possible thermal resistance between the fluids and the thermoelectrically active materials. In addition, the resistance to thermal stresses in the connecting material or the thermoelectric modules themselves has not been optimally resolved. Furthermore, the integratability of the thermoelectric modules in a heat exchanger, for example, has not been optimally resolved thus far.